static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
grpc_metadata_batch *initial_metadata,
uint32_t initial_metadata_flags,
grpc_connected_subchannel **connected_subchannel,
grpc_closure *on_ready) {
grpc_call_element *elem = elemp;
channel_data *chand = elem->channel_data;
call_data *calld = elem->call_data;
continue_picking_args *cpa;
grpc_closure *closure;
GPR_ASSERT(connected_subchannel);
gpr_mu_lock(&chand->mu_config);
if (initial_metadata == NULL) {
if (chand->lb_policy != NULL) {
grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy,
connected_subchannel);
}
for (closure = chand->waiting_for_config_closures.head; closure != NULL;
closure = grpc_closure_next(closure)) {
cpa = closure->cb_arg;
if (cpa->connected_subchannel == connected_subchannel) {
cpa->connected_subchannel = NULL;
grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, false, NULL);
}
}
gpr_mu_unlock(&chand->mu_config);
return 1;
}
if (chand->lb_policy != NULL) {
grpc_lb_policy *lb_policy = chand->lb_policy;
int r;
GRPC_LB_POLICY_REF(lb_policy, "cc_pick_subchannel");
gpr_mu_unlock(&chand->mu_config);
r = grpc_lb_policy_pick(exec_ctx, lb_policy, calld->pollset,
initial_metadata, initial_metadata_flags,
connected_subchannel, on_ready);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "cc_pick_subchannel");
return r;
}
if (chand->resolver != NULL && !chand->started_resolving) {
chand->started_resolving = 1;
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver,
&chand->incoming_configuration,
&chand->on_config_changed);
}
cpa = gpr_malloc(sizeof(*cpa));
cpa->initial_metadata = initial_metadata;
cpa->initial_metadata_flags = initial_metadata_flags;
cpa->connected_subchannel = connected_subchannel;
cpa->on_ready = on_ready;
cpa->elem = elem;
grpc_closure_init(&cpa->closure, continue_picking, cpa);
grpc_closure_list_add(&chand->waiting_for_config_closures, &cpa->closure, 1);
gpr_mu_unlock(&chand->mu_config);
return 0;
}
void grpc_client_config_set_lb_policy(grpc_client_config *c,
grpc_lb_policy *lb_policy) {
GPR_ASSERT(c->lb_policy == NULL);
if (lb_policy) {
GRPC_LB_POLICY_REF(lb_policy, "client_config");
}
c->lb_policy = lb_policy;
}
static void start_picking(pick_first_lb_policy *p) {
p->started_picking = 1;
p->checking_subchannel = 0;
p->checking_connectivity = GRPC_CHANNEL_IDLE;
GRPC_LB_POLICY_REF(&p->base, "pick_first_connectivity");
grpc_subchannel_notify_on_state_change(p->subchannels[p->checking_subchannel],
&p->checking_connectivity,
&p->connectivity_changed);
}
void grpc_client_config_set_lb_policy(grpc_client_config *c,
grpc_lb_policy *lb_policy) {
if (lb_policy) {
GRPC_LB_POLICY_REF(lb_policy, "client_config");
}
if (c->lb_policy) {
GRPC_LB_POLICY_UNREF(c->lb_policy, "client_config");
}
c->lb_policy = lb_policy;
}
static void start_picking(grpc_exec_ctx *exec_ctx, round_robin_lb_policy *p) {
size_t i;
p->started_picking = 1;
for (i = 0; i < p->num_subchannels; i++) {
p->subchannel_connectivity[i] = GRPC_CHANNEL_IDLE;
grpc_subchannel_notify_on_state_change(exec_ctx, p->subchannels[i],
&p->subchannel_connectivity[i],
&p->connectivity_changed_cbs[i]);
GRPC_LB_POLICY_REF(&p->base, "round_robin_connectivity");
}
}
static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
grpc_metadata_batch *initial_metadata,
uint32_t initial_metadata_flags,
grpc_connected_subchannel **connected_subchannel,
grpc_closure *on_ready, grpc_error *error) {
GPR_TIMER_BEGIN("pick_subchannel", 0);
channel_data *chand = elem->channel_data;
call_data *calld = elem->call_data;
continue_picking_args *cpa;
grpc_closure *closure;
GPR_ASSERT(connected_subchannel);
gpr_mu_lock(&chand->mu);
if (initial_metadata == NULL) {
if (chand->lb_policy != NULL) {
grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy,
connected_subchannel, GRPC_ERROR_REF(error));
}
for (closure = chand->waiting_for_config_closures.head; closure != NULL;
closure = closure->next_data.next) {
cpa = closure->cb_arg;
if (cpa->connected_subchannel == connected_subchannel) {
cpa->connected_subchannel = NULL;
grpc_exec_ctx_sched(
exec_ctx, cpa->on_ready,
GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1), NULL);
}
}
gpr_mu_unlock(&chand->mu);
GPR_TIMER_END("pick_subchannel", 0);
GRPC_ERROR_UNREF(error);
return true;
}
GPR_ASSERT(error == GRPC_ERROR_NONE);
if (chand->lb_policy != NULL) {
grpc_lb_policy *lb_policy = chand->lb_policy;
GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel");
gpr_mu_unlock(&chand->mu);
// If the application explicitly set wait_for_ready, use that.
// Otherwise, if the service config specified a value for this
// method, use that.
const bool wait_for_ready_set_from_api =
initial_metadata_flags &
GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET;
const bool wait_for_ready_set_from_service_config =
calld->wait_for_ready_from_service_config != WAIT_FOR_READY_UNSET;
if (!wait_for_ready_set_from_api &&
wait_for_ready_set_from_service_config) {
if (calld->wait_for_ready_from_service_config == WAIT_FOR_READY_TRUE) {
initial_metadata_flags |= GRPC_INITIAL_METADATA_WAIT_FOR_READY;
} else {
initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY;
}
}
// TODO(dgq): make this deadline configurable somehow.
const grpc_lb_policy_pick_args inputs = {
initial_metadata, initial_metadata_flags, &calld->lb_token_mdelem,
gpr_inf_future(GPR_CLOCK_MONOTONIC)};
const bool result = grpc_lb_policy_pick(
exec_ctx, lb_policy, &inputs, connected_subchannel, NULL, on_ready);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "pick_subchannel");
GPR_TIMER_END("pick_subchannel", 0);
return result;
}
if (chand->resolver != NULL && !chand->started_resolving) {
chand->started_resolving = true;
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result,
&chand->on_resolver_result_changed);
}
if (chand->resolver != NULL) {
cpa = gpr_malloc(sizeof(*cpa));
cpa->initial_metadata = initial_metadata;
cpa->initial_metadata_flags = initial_metadata_flags;
cpa->connected_subchannel = connected_subchannel;
cpa->on_ready = on_ready;
cpa->elem = elem;
grpc_closure_init(&cpa->closure, continue_picking, cpa);
grpc_closure_list_append(&chand->waiting_for_config_closures, &cpa->closure,
GRPC_ERROR_NONE);
} else {
grpc_exec_ctx_sched(exec_ctx, on_ready, GRPC_ERROR_CREATE("Disconnected"),
NULL);
}
gpr_mu_unlock(&chand->mu);
GPR_TIMER_END("pick_subchannel", 0);
return false;
}
static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
channel_data *chand = arg;
grpc_lb_policy *lb_policy = NULL;
grpc_lb_policy *old_lb_policy;
grpc_mdstr_hash_table *method_params_table = NULL;
grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
bool exit_idle = false;
grpc_error *state_error = GRPC_ERROR_CREATE("No load balancing policy");
if (chand->resolver_result != NULL) {
grpc_lb_policy_args lb_policy_args;
lb_policy_args.args = chand->resolver_result;
lb_policy_args.client_channel_factory = chand->client_channel_factory;
// Find LB policy name.
const char *lb_policy_name = NULL;
const grpc_arg *channel_arg =
grpc_channel_args_find(lb_policy_args.args, GRPC_ARG_LB_POLICY_NAME);
if (channel_arg != NULL) {
GPR_ASSERT(channel_arg->type == GRPC_ARG_STRING);
lb_policy_name = channel_arg->value.string;
}
// Special case: If all of the addresses are balancer addresses,
// assume that we should use the grpclb policy, regardless of what the
// resolver actually specified.
channel_arg =
grpc_channel_args_find(lb_policy_args.args, GRPC_ARG_LB_ADDRESSES);
if (channel_arg != NULL) {
GPR_ASSERT(channel_arg->type == GRPC_ARG_POINTER);
grpc_lb_addresses *addresses = channel_arg->value.pointer.p;
bool found_backend_address = false;
for (size_t i = 0; i < addresses->num_addresses; ++i) {
if (!addresses->addresses[i].is_balancer) {
found_backend_address = true;
break;
}
}
if (!found_backend_address) {
if (lb_policy_name != NULL && strcmp(lb_policy_name, "grpclb") != 0) {
gpr_log(GPR_INFO,
"resolver requested LB policy %s but provided only balancer "
"addresses, no backend addresses -- forcing use of grpclb LB "
"policy",
lb_policy_name);
}
lb_policy_name = "grpclb";
}
}
// Use pick_first if nothing was specified and we didn't select grpclb
// above.
if (lb_policy_name == NULL) lb_policy_name = "pick_first";
lb_policy =
grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args);
if (lb_policy != NULL) {
GRPC_LB_POLICY_REF(lb_policy, "config_change");
GRPC_ERROR_UNREF(state_error);
state =
grpc_lb_policy_check_connectivity(exec_ctx, lb_policy, &state_error);
}
channel_arg =
grpc_channel_args_find(lb_policy_args.args, GRPC_ARG_SERVICE_CONFIG);
if (channel_arg != NULL) {
GPR_ASSERT(channel_arg->type == GRPC_ARG_POINTER);
method_params_table = grpc_method_config_table_convert(
(grpc_method_config_table *)channel_arg->value.pointer.p,
method_config_convert_value, &method_parameters_vtable);
}
grpc_channel_args_destroy(chand->resolver_result);
chand->resolver_result = NULL;
}
if (lb_policy != NULL) {
grpc_pollset_set_add_pollset_set(exec_ctx, lb_policy->interested_parties,
chand->interested_parties);
}
gpr_mu_lock(&chand->mu);
old_lb_policy = chand->lb_policy;
chand->lb_policy = lb_policy;
if (chand->method_params_table != NULL) {
grpc_mdstr_hash_table_unref(chand->method_params_table);
}
chand->method_params_table = method_params_table;
if (lb_policy != NULL) {
grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
NULL);
} else if (chand->resolver == NULL /* disconnected */) {
grpc_closure_list_fail_all(
&chand->waiting_for_config_closures,
GRPC_ERROR_CREATE_REFERENCING("Channel disconnected", &error, 1));
grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
NULL);
}
if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) {
GRPC_LB_POLICY_REF(lb_policy, "exit_idle");
exit_idle = true;
chand->exit_idle_when_lb_policy_arrives = false;
}
if (error == GRPC_ERROR_NONE && chand->resolver) {
set_channel_connectivity_state_locked(
exec_ctx, chand, state, GRPC_ERROR_REF(state_error), "new_lb+resolver");
if (lb_policy != NULL) {
watch_lb_policy(exec_ctx, chand, lb_policy, state);
}
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result,
&chand->on_resolver_result_changed);
gpr_mu_unlock(&chand->mu);
} else {
if (chand->resolver != NULL) {
grpc_resolver_shutdown(exec_ctx, chand->resolver);
GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
chand->resolver = NULL;
}
grpc_error *refs[] = {error, state_error};
set_channel_connectivity_state_locked(
exec_ctx, chand, GRPC_CHANNEL_SHUTDOWN,
GRPC_ERROR_CREATE_REFERENCING("Got config after disconnection", refs,
GPR_ARRAY_SIZE(refs)),
"resolver_gone");
gpr_mu_unlock(&chand->mu);
}
if (exit_idle) {
grpc_lb_policy_exit_idle(exec_ctx, lb_policy);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "exit_idle");
}
if (old_lb_policy != NULL) {
grpc_pollset_set_del_pollset_set(
exec_ctx, old_lb_policy->interested_parties, chand->interested_parties);
GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel");
}
if (lb_policy != NULL) {
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change");
}
GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
GRPC_ERROR_UNREF(state_error);
}
static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
grpc_metadata_batch *initial_metadata,
uint32_t initial_metadata_flags,
grpc_connected_subchannel **connected_subchannel,
grpc_closure *on_ready) {
GPR_TIMER_BEGIN("pick_subchannel", 0);
channel_data *chand = elem->channel_data;
call_data *calld = elem->call_data;
continue_picking_args *cpa;
grpc_closure *closure;
GPR_ASSERT(connected_subchannel);
gpr_mu_lock(&chand->mu);
if (initial_metadata == NULL) {
if (chand->lb_policy != NULL) {
grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy,
connected_subchannel);
}
for (closure = chand->waiting_for_config_closures.head; closure != NULL;
closure = closure->next_data.next) {
cpa = closure->cb_arg;
if (cpa->connected_subchannel == connected_subchannel) {
cpa->connected_subchannel = NULL;
grpc_exec_ctx_sched(exec_ctx, cpa->on_ready,
GRPC_ERROR_CREATE("Pick cancelled"), NULL);
}
}
gpr_mu_unlock(&chand->mu);
GPR_TIMER_END("pick_subchannel", 0);
return true;
}
if (chand->lb_policy != NULL) {
grpc_lb_policy *lb_policy = chand->lb_policy;
int r;
GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel");
gpr_mu_unlock(&chand->mu);
const grpc_lb_policy_pick_args inputs = {calld->pollent, initial_metadata,
initial_metadata_flags,
&calld->lb_token_mdelem};
r = grpc_lb_policy_pick(exec_ctx, lb_policy, &inputs, connected_subchannel,
NULL, on_ready);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "pick_subchannel");
GPR_TIMER_END("pick_subchannel", 0);
return r;
}
if (chand->resolver != NULL && !chand->started_resolving) {
chand->started_resolving = true;
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result,
&chand->on_resolver_result_changed);
}
if (chand->resolver != NULL) {
cpa = gpr_malloc(sizeof(*cpa));
cpa->initial_metadata = initial_metadata;
cpa->initial_metadata_flags = initial_metadata_flags;
cpa->connected_subchannel = connected_subchannel;
cpa->on_ready = on_ready;
cpa->elem = elem;
grpc_closure_init(&cpa->closure, continue_picking, cpa);
grpc_closure_list_append(&chand->waiting_for_config_closures, &cpa->closure,
GRPC_ERROR_NONE);
} else {
grpc_exec_ctx_sched(exec_ctx, on_ready, GRPC_ERROR_CREATE("Disconnected"),
NULL);
}
gpr_mu_unlock(&chand->mu);
GPR_TIMER_END("pick_subchannel", 0);
return false;
}
static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
channel_data *chand = arg;
grpc_lb_policy *lb_policy = NULL;
grpc_lb_policy *old_lb_policy;
grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
bool exit_idle = false;
grpc_error *state_error = GRPC_ERROR_CREATE("No load balancing policy");
if (chand->resolver_result != NULL) {
lb_policy = grpc_resolver_result_get_lb_policy(chand->resolver_result);
if (lb_policy != NULL) {
GRPC_LB_POLICY_REF(lb_policy, "channel");
GRPC_LB_POLICY_REF(lb_policy, "config_change");
GRPC_ERROR_UNREF(state_error);
state =
grpc_lb_policy_check_connectivity(exec_ctx, lb_policy, &state_error);
}
grpc_resolver_result_unref(exec_ctx, chand->resolver_result);
}
chand->resolver_result = NULL;
if (lb_policy != NULL) {
grpc_pollset_set_add_pollset_set(exec_ctx, lb_policy->interested_parties,
chand->interested_parties);
}
gpr_mu_lock(&chand->mu);
old_lb_policy = chand->lb_policy;
chand->lb_policy = lb_policy;
if (lb_policy != NULL) {
grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
NULL);
} else if (chand->resolver == NULL /* disconnected */) {
grpc_closure_list_fail_all(
&chand->waiting_for_config_closures,
GRPC_ERROR_CREATE_REFERENCING("Channel disconnected", &error, 1));
grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
NULL);
}
if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) {
GRPC_LB_POLICY_REF(lb_policy, "exit_idle");
exit_idle = true;
chand->exit_idle_when_lb_policy_arrives = false;
}
if (error == GRPC_ERROR_NONE && chand->resolver) {
set_channel_connectivity_state_locked(
exec_ctx, chand, state, GRPC_ERROR_REF(state_error), "new_lb+resolver");
if (lb_policy != NULL) {
watch_lb_policy(exec_ctx, chand, lb_policy, state);
}
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result,
&chand->on_resolver_result_changed);
gpr_mu_unlock(&chand->mu);
} else {
if (chand->resolver != NULL) {
grpc_resolver_shutdown(exec_ctx, chand->resolver);
GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
chand->resolver = NULL;
}
grpc_error *refs[] = {error, state_error};
set_channel_connectivity_state_locked(
exec_ctx, chand, GRPC_CHANNEL_SHUTDOWN,
GRPC_ERROR_CREATE_REFERENCING("Got config after disconnection", refs,
GPR_ARRAY_SIZE(refs)),
"resolver_gone");
gpr_mu_unlock(&chand->mu);
}
if (exit_idle) {
grpc_lb_policy_exit_idle(exec_ctx, lb_policy);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "exit_idle");
}
if (old_lb_policy != NULL) {
grpc_pollset_set_del_pollset_set(
exec_ctx, old_lb_policy->interested_parties, chand->interested_parties);
GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel");
}
if (lb_policy != NULL) {
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change");
}
GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
GRPC_ERROR_UNREF(state_error);
}
static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
bool iomgr_success) {
channel_data *chand = arg;
grpc_lb_policy *lb_policy = NULL;
grpc_lb_policy *old_lb_policy;
grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
int exit_idle = 0;
if (chand->incoming_configuration != NULL) {
lb_policy = grpc_client_config_get_lb_policy(chand->incoming_configuration);
if (lb_policy != NULL) {
GRPC_LB_POLICY_REF(lb_policy, "channel");
GRPC_LB_POLICY_REF(lb_policy, "config_change");
state = grpc_lb_policy_check_connectivity(exec_ctx, lb_policy);
}
grpc_client_config_unref(exec_ctx, chand->incoming_configuration);
}
chand->incoming_configuration = NULL;
if (lb_policy != NULL) {
grpc_pollset_set_add_pollset_set(exec_ctx, lb_policy->interested_parties,
chand->interested_parties);
}
gpr_mu_lock(&chand->mu_config);
old_lb_policy = chand->lb_policy;
chand->lb_policy = lb_policy;
if (lb_policy != NULL || chand->resolver == NULL /* disconnected */) {
grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
NULL);
}
if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) {
GRPC_LB_POLICY_REF(lb_policy, "exit_idle");
exit_idle = 1;
chand->exit_idle_when_lb_policy_arrives = 0;
}
if (iomgr_success && chand->resolver) {
set_channel_connectivity_state_locked(exec_ctx, chand, state,
"new_lb+resolver");
if (lb_policy != NULL) {
watch_lb_policy(exec_ctx, chand, lb_policy, state);
}
GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
grpc_resolver_next(exec_ctx, chand->resolver,
&chand->incoming_configuration,
&chand->on_config_changed);
gpr_mu_unlock(&chand->mu_config);
} else {
if (chand->resolver != NULL) {
grpc_resolver_shutdown(exec_ctx, chand->resolver);
GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
chand->resolver = NULL;
}
set_channel_connectivity_state_locked(
exec_ctx, chand, GRPC_CHANNEL_FATAL_FAILURE, "resolver_gone");
gpr_mu_unlock(&chand->mu_config);
}
if (exit_idle) {
grpc_lb_policy_exit_idle(exec_ctx, lb_policy);
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "exit_idle");
}
if (old_lb_policy != NULL) {
grpc_pollset_set_del_pollset_set(
exec_ctx, old_lb_policy->interested_parties, chand->interested_parties);
GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel");
}
if (lb_policy != NULL) {
GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change");
}
GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
}
